J/ApJ/678/635ivo://CDS.VizieR/J/ApJ/678/635doi:10.26093/cds/vizier.16780635CDSMyers A.D.Richards G.T.Brunner R.J.Schneider D.P.Strand N.E.,Hall P.B.Blomquist J.A.York D.G.2017-06-12T08:24:36Z2010-10-28T21:07:46ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frspectroscopic-binary-starsredshiftedquasarsWe present spectroscopy of binary quasar candidates, with component separations of 3"<={Delta}{theta}<6", selected from SDSS DR4 using kernel density estimation (KDE). Of our 27 new quasar pair observations, 10 are binary quasars, which doubles the number of known g<21 binaries with 3"<={Delta}{theta}<6" separations. Several of our observed binaries are wide-separation lens candidates that merit additional higher resolution spectroscopy, as well as deep imaging to search for lensing galaxies. Our candidates are initially selected by UV excess (u-g<1), but are otherwise selected irrespective of the relative colors of the quasar pair, and we thus use them to suggest optimal color similarity and photometric redshift approaches for targeting binary quasars or projected quasar pairs. We find that a third or more of all binary quasars have quite dissimilar components on the basis of a typical color similarity criterion ({chi}^2^_color_<~20). From a sample that is complete on proper scales of 23.7h^-1^kpc<R_prop_<29.9h^-1^kpc, we determine the projected quasar correlation function.2008ApJ...678..635Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/678/635CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010)VII/258 : Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010)J/AJ/135/496 : SDSS quasar lens search. II. (Inada+, 2008)J/ApJS/175/29 : Spectroscopy of QSO pairs (Marble+, 2008)J/ApJ/658/99 : Pairs of QSO in SDSS-DR4 (Myers+, 2007)J/AJ/131/1 : Binary quasars in the SDSS (Hennawi+, 2006)J/MNRAS/311/456 : RIXOS source catalogue (Mason+, 2000)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/678/635https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/678/635http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/678/635https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/678/635https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/678/635http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/678/635GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/678/635/binQSO (DR4 KDE binary quasars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/678/635/binQSO?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/678/635/binQSO?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/678/635/binQSO?GETtext/xml+votable180.050000true142.5617333342.010752780.005555555555555556Cone search capability for table J/ApJ/678/635/table5 (Previously identified DR4 KDE binary quasar candidates with 3"<={Delta}{theta}<6")https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/678/635/table5?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/678/635/table5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/678/635/table5?GETtext/xml+votable180.050000true42.282408330.654755560.0055555555555555566/4354 5048 5306 5663 5733 5785 5788 6003 6118 7168 7208 7210 7363 7424 7508 7563 8330 8352 8922 9058 9268 9320 9359 9458 9813 10094 10189 10396 10925 10938 10974 11064 11316 11341 11431 11456 11814 11913 11955 12387 17756 19426 25934 26353 26555 27500 27852 27865 27872 281853.588997330618193e-19 4.653515163505597e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/678/635?format=asciiOpticaldefaultJ/ApJ/678/635/binQSODR4 KDE binary quasarszpeakPeak of photometric redshift rangesrc.redshift.photfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPSimbad column added by the CDSmeta.codecharSDSSSDSS designation (JHHMMSS.ss+DDMMSS.s or JHHMM+DDMMA)meta.id;meta.mainchargmagg-band magnitude not corrected for Galactic extinctionmagphot.mag;em.opt.BfloatzlowLowest extent of photometric redshift rangesrc.redshift.photfloatzhighHighest extent of photometric redshift rangesrc.redshift.photfloatpr(z)probability of the true redshift lying in this rangestat.fit.goodnessfloatzSDSS? SDSS spectroscopic redshift (1)src.redshiftfloatnullablen_z[*NFPO] Note on z (2)meta.notecharz? Spectroscopic redshift from KPNO data (1)src.redshiftfloatnullableu_z[D?] when redshift is based on a single emission line (3)meta.code.error;src.redshiftcharchi2{chi}^2^ color: each pair's color similarity statistic (4)stat.fit.chi2floatf_Dphi[*] Possible lens (5)meta.codecharDphiAngular pair separationarcsecpos.angDistancefloatSimbadNameSimbad column added by the CDSmeta.idcharSloanDisplay the SDSS data for this quasarmeta.ref.urlcharDR7Display the details of the photometry in SDSS-DR7 (Cat. II/294)meta.ref.urlcharRAJ2000Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000)pos.eq.dec;meta.mainJ/ApJ/678/635/table5Previously identified DR4 KDE binary quasar candidates with 3"<={Delta}{theta}<6"DphiAngular pair separationarcsecpos.angDistancefloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintocObject categories (1)src.classcharSDSSSDSS designation (JHHMMSS.ss+DDMMSS.s or JHHMM+DDMMA) (2)meta.id;meta.mainchargmagg-band magnitudemagphot.mag;em.opt.BfloatzlowLowest extent of photometric redshift rangesrc.redshift.photfloatzpeakPeak of photometric redshift rangesrc.redshift.photfloatzhighHighest extent of photometric redshift rangesrc.redshift.photfloatpr(z)probability of the true redshift lying in this rangestat.fit.goodnessfloatRem[*mchf] Remark on object (3)meta.notecharz? Redshift from litteraturesrc.redshiftfloatnullablef_z[SIDio] Flag on redshifts (4)meta.codecharchi2{chi}^2^ color: each pair's color similarity statistic (5)stat.fit.chi2floatSimbadNameSimbad column added by the CDSmeta.idcharSloanDisplay the SDSS data for this quasarmeta.ref.urlcharDR7Display the details of the photometry in SDSS-DR7 (Cat. II/294)meta.ref.urlcharNEDSimbad column added by the CDScharRAJ2000Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000)pos.eq.dec;meta.main